A diamond's cost is based on the characteristics known as the "5 C's". Clarity, Color, Certification and Cut (proportion) are the quality elements which together with the Carat Weight determine the value of a stone. The closer a diamond grades to the left of one or all of these scales the rarer and the more costly it will be. While clarity is frequently assumed to be the most important factor of all the "C's", in fact, color and cut (especially cut) have a more profound affect on the visual appearance of a diamond.
Carat Weight
Carat is the unit of weight for all gemstones. One carat is subdivided into 100 "points". Therefore a diamond measuring 75 points is 3/4 carat in weight, or 0.75ct. There are five carats in a gram. The word "carat" comes from the seed of the carob tree pod which is found in tropical climates. These seeds were used until this century to weigh precious gems.
Clarity
A diamond's clarity is determined by the number, nature, position, size and color of internal characteristics called "inclusions" and surface features called "blemishes". These irregularities occurred in the liquid magna (volcanic rock) within which the diamond was created. Diamonds are mostly pure carbon, however, during crystallization other minerals nearby, or even other bits of carbon forming more quickly may have become trapped within the cooling mass. These show themselves as the various characteristics which make up the clarity of a diamond (included crystals, feathers, clouds etc). Clarity is measured on a scale ranging from pure (flawless) to heavily included (I-3). The clarity of a diamond is graded by using 10X magnification under good lighting by an experienced grader. The final clarity grade is usually determined by how easy the inclusions and blemishes are for the grader to see.
Color
Ideally, a diamond should have no color at all, like a drop of spring water. Increasing degrees of body color are measured on a scale ranging from no color at all (D) to deeply colored (Z). Beyond "Z" is the range where the diamond's color is vivid and rich, called "fancy colors". Diamonds of known color are used as comparison stones for color grading. Grading is done by comparing the diamond to be graded against these "master stones" under either artificial or natural north daylight ( in the Northern Hemisphere). A machine called the "Colorimeter" can be used for color grading but there is no substitute for the trained human eye.
Cut
Cut, sometimes the forgotten "C", ensures that a given stone has maximum brilliance and sparkle which would not be the case were the stone cut for weight alone.
We use the following scale to grade a stone on it's overall appearance. The proportion page shows angles and percentages for round brilliant cut diamonds; but angles and percentages are for diamond cutters and graders. Simply put, when looking at a diamond, if it doesn't catch your eye or if it doesn't flash in the light, it's probably not well cut. Good cutting is what brings fire to the ice.
The cut of a diamond will determine how light is refracted back out and this will determine the fire and brilliance of the stone. A well cut diamond refracts nearly all the light entering it out of the top (crown) and sides. This results in the form of greater fire (colored light) and more brilliance (white light).
Diamond Certification
A certificate is a "blueprint" of a loose diamond. Also called the diamond grading report or diamond dossier, it tells you the diamond's exact measurements and weight, as well as the details of its cut and quality. It precisely points out all the individual characteristics of the stone. Certificates also serve as proof of the diamond's identity and value. Certification Protects Diamond Buyers
A certificate is not the same thing as an appraisal. A certificate describes the quality of a diamond, but it does not place a monetary value on the gem.
Diamond Certification Laboratories are independently run. The labs grade and check the diamonds to ensure the inspected diamonds have not been treated and are of natural origin. They then issue Certificates with each diamond to assure the owner that the diamond is free of all known treatments and enhancements. It also confirms the diamond is natural and not a synthetic diamond.
Some labs place laser inscription on the diamond's girdle, matching the certificate number, providing added confidence.
Labs & Certificates
Where a diamond has been assessed by a laboratory it is termed a certificated or certified stone. The codes for the different laboratories used are as follows:
Code:
Laboratory:
Code:
Laboratory:
ADL
Antwerp Diamond Laboratory
GIA
Gemological Institute of America
AGS
The American Gem Society
GII
National Gemological Institute of Israel
CIB
CIBJO (Europe)
GIL
Gem Information Laboratory
CSA
Jewelery Council of South Africa
GTL
Gem Testing Laboratory of Great Britain
DGL
Diamond Grading Laboratories (London)
NGL
Northern Gemological Laboratories (UK)
EGI
European Institute (Antwerp)
HRD
Diamond High Council (Antwerp)
EGL
European Institute (Antwerp & London)
HRG
Heinz R Gartner, DGemG, FGA (Germany)
PNF
P N Ferstenberg Pbv A
IGI
International Institute (Antwerp)
GAG
Gesellschaft fur Angewandte Gemologies
PSL
Precious Stone Laboratory (London)
GAN
Gemological Institute of Antwerp
VPT
Verena Pagel-Theisen, DGemG FGA (Germany)
WG
Werner Galia, DGem, (Germany)
Accurate assessment of a diamond is only possible prior to being set. Once the stone is set even a qualified diamond grader cannot precisely determine color, size and purity. The Diamond Certificate is only reliable if it is from an independent and qualified laboratory. Besides the international standards to which these laboratories grade, qualified laboratories have the necessary equipment to check for Synthetics, Stimulants and treatments.
Synthetic and treated diamonds have a significantly lower value, and this information should be disclosed.
It is crucial when choosing a diamond to review the diamond certificate, also known as a Diamond Grading Report, especially larger diamonds greater than 0.99 carat. This report documents the internationally recognized characteristics of a diamond, its carat weight, color, clarity, cut.
Know the four C's of the diamond you are looking at to ensure that good quality comes with a fair price.
Select the Cut or shape that pleases you. The proportions of the diamond will determine its brilliance.
As for Color, the difference in ratings is very slight, however, variance of only one grade can change the price by 10% or more.
Regarding Clarity, most diamonds have some blemishes and inclusions. Choose diamonds that hide these imperfections down deep in the stone or where the imperfections are to the side and can be hidden by prongs or bezels.
Always inspect the diamond before mounting.
Get a Gemological Institute of America (GIA) certificate, or a European Gemological Laboratory (EGL) Certificate, or a (IGI) Certificate of the diamond you are buying. This ensures honesty and sound investment.
If you want to upgrade your diamond after couple of years be sure to have the option of getting full credit towards the upgrade.
Popular Diamond Shapes
Round - Also called Brilliant, this is the diamond that is a favorite in engagement rings. Emerald Cut - So-called because emeralds are often cut this way, rectangular or square, with facets polished diagonally across the corners. Marquise - A pointed boat shape, usually long and narrow. In a ring, it tends to make the fingers look slim. Pear Shape - popular in rings and often used in pendants. The world's largest cut diamond, Cullinan I, mounted in the British Royal Sceptre, is a pear shape. Oval - an adaptation of the brilliant shape. The marquise, pear shape and oval all appear to be larger than a brilliant of the same carat weight.
The four C's
CUT
Diamonds are fashioned into a number of shapes, depending on the nature of the rough stone. The eight most popular shapes are round, marquise, pear, oval, emerald, princess, radiant, and heart.
A common question: What is the cutting differences between Princess cut diamond and a Radiant cut diamond?
Generally speaking the princess cut retains more of the rough diamond by maintaining the shape of the rough stone that exists before cutting begins. This means manufacturers focus on maximizing "yield from the rough" rather than on the beauty of the diamond. In part, far more princesses are available on the market today because they are cheaper for manufacturers to produce. A radiant cut diamond is a combination cut between Round brilliant on top, and Emerald step cut on the pavilion area.
The choice is largely a matter of personal taste. Whatever your preference, a well cut diamond is the work of a master diamond cutter, since it is the cut that enables the diamond to reflect light, creating scintillation and sparkle. When a diamond is well proportioned, light is reflected from one facet to another and dispersed through the top of the stone as rainbows of color.
Every diamond regardless of its shape gets it brilliancy and scintillation by cutting and polishing the diamond facets to allow the maximum amount of light that enters through its top to be reflected and dispersed back through its top.
A correctly cut, "Ideal cut" stone is pictured in diagram 1. As you can see if the angles are correct the light that enters is dispersed properly back through the diamond's top facets. When a stone is cut too shallow (diagram 2) or too deep (diagram 3) the light that enters through the top is allowed to escape through the diamond's bottom and does not allow the maximum beauty of the diamond to be realized.
A well cut diamond is beautiful because it's very brilliant. Of all the variables affecting the value of a diamond, the cut is the most crucial.
Diamonds are sold by weight in carats. The heavier the diamond, the more valuable it is. But bigger does not necessarily mean better. Quality is found in diamonds of all sizes
The carat weight sacrificed for the purpose of good to ideal proportions also factors into the price. In the illustration to the right, the shaded portion represents wasted crystal. All three are one carat diamonds; however, the two on the right are poorly proportioned and thus much less expensive.
The most important feature in evaluating a diamond cut is the accurate three-dimensional model. All examinations, calculations, and grading are done on this model. The model contains complete linear and angular information on each and every facet, including directional angles data which is crucial for symmetry observations and grading.
Figure 1
Figure 1 shows a summary of the diamond's linear and angular measurements from the diamond's side view. We can see the diamond's diameter, table size, total depth, crown height, girdle thickness, pavilion depth, culet size, average crown angle, and average pavilion angle. These average measurements are traditionally used for grading the diamond proportions.
Figure 2
Figure 3
In Figure 2 we can see the new angular measurements on each and every facet of the diamond, from the diamond's top and bottom views. This information is a vital source for symmetry and ray tracing calculations. Gem lab research has shown that no light performance observation or grading can be complete without using the individual facet angle information.
Figure 3 shows us the directional angle of every facet, from the diamond's top view. Similar data is available for the bottom part of the diamond. The numbers in this image represent the directional angle of the facet, starting at zero for the first bezel facet measured.
Figure 4
Figure 5
Figure 4 shows a different transformation of this data, usually more useful for diamond manufacturers at the quality assurance stage. These numbers are the directional shift of every facet from the optimal direction they should be at, according to the diamond's symmetry axes. Thus, we can see positive as well as negative directional shifts, depending on whether the facet is shifted clockwise or counterclockwise. A directional shift value of zero means that the facet is perfectly positioned on the diamond.
Another useful view is the top-down symmetry view, shown in Figure 5. This view shows the diamond surface as completely transparent, to allow an unobstructed view of the diamond's symmetry problems. In this example we can easily spot a slight crown-pavilion twist problem by examining the misalignment of the upper- and lower- girdle halves. Similar and more severe problems can be easily spotted with this view.
Figure 6
Finally, Figure 6 shows an interesting example of using the three-dimensional view.
If we look at the image on the left, we see a white area on the upper-girdle halves, representing severe light leakage from this area of the diamond. The girdle thickness at the meeting point of the upper-girdle halves and the girdle, 6.4%, is much thicker than the girdle thickness at the meeting points of the crown bezels and the girdle around it, 4.0% and 5.3%. This is a result of a common practice among diamond manufacturers known as girdle painting. This practice evolved when manufacturers wanted to add weight to their diamonds at the most obvious place for doing this - the girdle, but in a way that will not harm the diamonds' proportion grade. Since many gem labs only measure or grade the girdle thickness at the meeting points between the crown bezels and the girdle, adding thickness and thus weight, to the meeting points of the upper-girdle halves and the girdle seemed like the natural thing to do.
However, as cut grading systems change to include light performance considerations, this practice can no longer continue without consequences.
The standard brilliant comprises:
Upper:
1 Table facet
8 Star facets
8 Kite or Upper Main Facets
16 Upper Girdle facets
Total facets: 33 Crown Facets
Girdle:
This is the waist band in the middle, and is sometimes faceted.
Pavilion:
8 Pavilion
16 Lower Girdle
1 Culet
Total facets: 25 Pavilion Facets
Thus there are 58 facets in total.
CARAT
Carat is actually a measurement of weight, NOT size. However, it should be relative to size. One carat is divided into 100 points. 1.00 ct is equal to .20 grams. Two diamonds of equal quality can have different values depending on their cut, color and clarity.
Carat is the easiest of the 4 C's to determine. One carat is divided into 100 "points," so that a diamond of 75 points, for example, weighs .75 carats, 50 points weighs 1/2 carat etc. Fine quality can be found in diamonds of all carat weights. If a diamond is cut for beauty, and not maximum yield in weight, it is more desirable than a heavier weight and lumpier stone, and will have the appearance of a larger stone.
COLOR
Diamonds are found in a range from colorless to yellowish, and judged according to a color grading scale from "D", which is totally colorless through "Z" which is vivid yellow. It is the colorless diamond that is most valued because it is the most rare. The difference between one color grade and another is very subtle, particularly to the untrained eye. Although increasing shades of yellow reduce the value of a diamond, they do not necessarily reduce its beauty. If a diamond is well cut, its refraction and dispersion of light will often disguise certain degrees of coloration. The average stone bought carries an I or J grading for its Color. In addition to diamonds listed from D to Z, there are twelve other colors called Fancies, and as the name implies, they are expensive.
Color:
Description:
D
Pure White - the most prized color
E
Exceptional white - colorless group
F
Excellent white - colorless group
G
Good white - colorless group
H
White - colorless group
I
Slightly tinted white/ white when viewed from top
J
Slightly tinted white/ commercial white
K
Tinted white/ still acceptable white when mounted
L
Tinted white/ needs yellow setting to look its best
M
Slightly yellowish/Tinted color-champagne
N
Slightly yellowish/Tinted color-champagne
O-R
Yellowish/Tinted color
S-Z
Yellow/Tinted color
CLARITY
Most diamonds contain tiny natural birthmarks called inclusions. Most are not visible with the naked eye but can be seen with 10X magnification. Inclusions interfere with the dispersion of light and therefore the diamond's brilliance. The fewer and smaller the inclusions, the rarer the stone and higher the price.
While inclusions do not generally affect the diamond's beauty and usually cannot be seen, their presence reduces the price. Clarity is graded on a scale with a range from internally flawless (IF), very very small inclusions (VVS1-VVS2), very small inclusions (VS1-VS2), small inclusions (SI1-SI2) to imperfect (I1-I2-I3) with eye visible inclusions.
Practically all diamonds contain naturally occurring internal characteristics called inclusions. The size, nature, location and amount of inclusions determine a diamond’s clarity grade and thus its cost. One unique advantage of the Ideal Cut is that its sparkle can mask otherwise noticeable inclusions.
FL - IF
VVS 1 -VVS 2
VS 1 - VS 2
SI 1 - SI 2
I 1 - I 3
No inclusions visible by an expert under 10X magnification.
FL=Flawless
IF=Internally Flawless
Minute-extremely difficult to find under 10X magnification.
VVS=Very, Very Slight inclusions
Minor-Difficult to
find under 10X magnification.
VS=Very Slight inclusions
Noticeable, relatively easy to find under 10X magnification.
SI=Slight Inclusions
Obvious under 10X magnification-usually to the naked eye.
I=Included
Diamond Enhancements:
Laser Drilling
Lasers have been used commercially for drilling diamonds since the late 1960's. It is possible to improve the appearance of diamonds which have dark magnetic pyrites and magnetite inclusions by drilling into the diamond surface and then bleaching out or chemically dissolving the inclusions with an etching fluid such as sulphuric acid and saltpetre. The drill holes are then usually filled with a highly refractive wax or synthetic resin and this protects the drill chanel against penetration of dust and dirt. This can be affected if your diamond is ever subjected to heat or acid as often is the case when being set in jewellery or worked on by an unsuspecting working jewler. Since this treatment is fairly permanent, GIA Diamond Lab will grade Clarity enhanced-laser drilled diamonds.
Filled Diamonds
This is a more recent enhancement by which inclusions and especially cracks which break the surface can be made more transparent and hence improve the clarity of a cut diamond. The cracks are filled under pressure (50 atmospheres) in a vacuum at high temperature (400 degrees Celcius) with a glass of refractive index close to that of diamond at 2.417. A color flash similar to that on the surface of a detergent bubble is visible due to the juxtaposition of the two different materials. Unfortunately the process though widely used is neither durable or permanent and will not withstand the cutting and repair processes involved in jewelry goldsmithing.
Since this process is not permanent, GIA Diamond Lab will not grade Clarity enhanced-filled diamonds.
Some Notable Diamonds:
Such mystique surrounds diamonds, that the largest have been given names. Some historic diamonds include:
The Hope Diamond:
Cut from a 132.5 carat gem, this 45.52 carat blue cushion is now on display at the Smithsonian Institution and is known for its famous curse. Most of those who owned it died in revolutions, suffered scandal, or met with financial ruin.
The Cullinan:
The two largest gem diamonds in existence were cut from the same huge rough stone, a 3,106 carat diamond weighing IVi pounds and measuring 2 x 2 % x 4 inches. It was discovered in 1705 in a South African mine and was presented to King Edward VII of England. The stone was cut to form Cullinan 1. A second cleavage produced the 317.4 carat Cullinan II, now mounted in the British Crown, plus 116 other gems.
The Taylor-Burton:
This 69.42 carat pear was cut from a 240.8 carat rough found in 1966. It was sold at auction to Cartier of New York for $1,050,000 and purchased the next day by actor Richard Burton for his wife, at the time, actress Elizabeth Taylor.
The Regent:
This 140.5 carat cushion brilliant, now on display in the Louvre, was once one of the French crown jewels. It graced the hat of Marie Antoinette and later the hilt of Napoleon's sword.
The Florentine:
Most famous of the world's lost diamonds is this 137.27 carat yellow, whose history dates from the 15th Century. After a succession of owners, it became a part of the Austrian crown jewel collection. The gem disappeared during World War I when the Austrian imperial family was forced into Swiss exile.
Blood Diamonds:
Some diamonds have helped fund devastating civil wars in Africa, destroying the lives of millions. Conflict diamonds are those sold in order to fund armed conflict and civil war. Profits from the trade in conflict diamonds, worth billions of dollars, were used by warlords and rebels to buy arms during the devastating wars in Angola, the Democratic Republic of Congo (DRC) and Sierra Leone. Wars that have cost an estimated 3.7 million lives.
Conflict diamonds are diamonds illegally traded to fund conflict in war-torn areas, particularly in central and western Africa. The United Nations (UN) defines conflict diamonds as "...diamonds that originate from areas controlled by forces or factions opposed to legitimate and internationally recognized governments, and are used to fund military action in opposition to those governments, or in contravention of the decisions of the Security Council." These diamonds are sometimes referred to as "blood diamonds."
While the wars in Angola and Sierra Leone are now over, and fighting in the DRC has decreased, the problem of conflict diamonds hasn't gone away. Diamonds mined in rebel-held areas in Côte d'Ivoire, a West African country in the midst of a volatile conflict, are reaching the international diamond market. Conflict diamonds from Liberia are also being smuggled into neighboring countries and exported as part of the legitimate diamond trade.
At our store, "Diamond Connection", our supply of diamonds is from sources that are all free of any conflicts!
What's being done to stop conflict diamonds?
A major milestone occurred in 2003, when the government-run initiative known as the Kimberley Process was introduced to stem the flow of conflict diamonds. The Kimberley Process Certification Scheme (KPCS) imposes requirements on participants to certify that shipments of rough diamonds are conflict-free.
Know the four C's of the diamond you are looking at to ensure that good quality comes with a fair price.
